tom, the suspect, dzhokhar tsarnaev, he's sedated in the hospital. he's the only person right now who knows why any of this occurred. but if they can't question him yet, what are they focusing on on the investigation? walk us through a little bit about what's going on behind the scenes. >> well, they're doing what they would have been doing even if he could talk. that is going through every possible e-mail, telephone conversation, well they can't get the conversation, but at least who he contacted or received calls for. going to every person identified to interview them about what they know about him and his intentions, if possible. interviewing all of the former classmates and teachers and neighbors and relatives, and although as you heard this week, most of them have nothing but glowing accounts of how great a kid he was. so they'll probably hear much of that again. but they will go through trying to really identify everybody he's been in contact with for as far back as they can go. >> you know, a lot of questions have been raised. the russians, th